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SBC Ally cylinder heads

One of my many projects is the 79 vette, I need to get this sorted for the summer as eldest daughter is getting married and wants to be taken in the Vette, I need to replace the clutch which I have and I have slowly been buying other engine bits so thought I would give it a spruce up at the sametime,

The engine gives out a MAHUSIVE 195bhp by all accounts so I will be ditching the air pump, cast iron inlet, fitting an ally inlet, ally air cleaner, headers and a dual exhaust, modify the advance curve and rebuild the quadrajet which should perk the old girl up a bit.

However as all this is going on I started to think about a pair of ally heads, should breath better and will take a bit more weight off the front end as well, anyone have any thoughts on what heads would suit, are the cheap ones really that bad or is it just some of them, it's not going to be a drag car but a little perking up when the loud pedal is hit would be nice so I may well get a new cam as well, nothing wild just a bit lumpier but would need to know for sure what heads I would be using.

If the cheap heads are crap then it will stay with the iron ones

Apart from the ally sump the rest of the engine will be untouched as oil pressure is excellent and it doesn't smoke or rattle.

Any thoughts, ideas or advice greatfully received, even if it's don't do it.

Driving 'round the M25 so fast the centrifugal force is forcing my face against the side window!

Posts

593

A few of our CCCUK members have sourced later set of SBC ally heads, say from a C4 Vette. A relatively cheap way to improve things. I'm guessing that stock lo-comp pistons will be a limiting factor.... there are cams you can source that can make the best of low compression engines......

In the past few years I've used both Dart and Canfield and been happy with both. Personally I wouldn't use the cheap heads as have heard plenty of horror stories although a few indicate that using decent parts with the bare heads is more of a success. I do know of somebody running good times on a set of Chinese on a Tri Chevy.

Thanks for the replies gents, not thought about c4 vette heads so that could be a way forward.

I had heard that the chinese cheap set up's were awful but only from third parties never from an owner, usually american's who hate anything that isn't built or made in the USA (sorry MJ I know you have a whole lot more knowledge than most of us so you are excluded from the previous statement).

It was only an idea due to the other works going on, I'll do a little digging and see what the costs are going to be. I know that the other items I will be doing will significantly improve things and as I said it's not a drag car.

Well... youve hit a 'hot button' of mine here, but Ill try to be as objective as possible...still, no matter what you do, never EVER use anything from red china. Period.

OK, past socio-political and moral/ethical reasons, practically, the heads [and anything else] from red china are junk. IF you get a decent set out of the box, you might get by using them on a race car; as Mr Plumpcars said, he knows of people 'running good times' with a set. The likelihood of any sort of longevity is very low. Anecdotal evidence says that you will run about a 33% chance of a bad casting right out of the box. If you make it past that hurdle, you will drop a seat eventually. The ONLY way to make that junk work and last well is to take a bare casting, have it sonic and pressure checked, and if its a good one, completely rebuild it using quality parts. Then of course, you coulda bought some Darts or Brodix or whatever in the first place...

The late Corvette heads will work fine, but then you hafta use later valve covers; EVERYONE knows that God gave us small block Chevrolets with 4 bolts around the outside of the valve cover, not in the middle...

Since its not a race car, the 50 lbs or whatever difference isnt gonna make that much difference anyway. My own ever so humble opinion, assuming you wanted to change heads, would be to go to some earlier iron heads wit 2.02 valves and 64 or even 68cc chambers. They will flow better than what youve got - especially with a few hours spent with you and your grinder matching ports and smoothing runners - and will give you a bump in compression which will wake things up a bit. Be sure to rebuild using quality seats, guides and such and posi-lock seals.

As far as intakes go, I like the LT1 /Z28 unit, but thats just me. Plus , theyre drilled for a square flange Holley, so there goes your Q Jet plan. You can work with an aluminum L82 piece and get good results also, but if you go aftermarket, use a dual plane please; this isnt a race car...

Headers...well, you know my story on headers...

a true 2 1/2" dual exhaust will work wonders. Im a little outta the loop, but see if 'Pypes' makes a kit; know a couple of guys that race in Pure Stock and F.A.S.T. and swear by em.

Cam... again, you know my story. There are several 'modern' profiles that apparently do wonders. BITD, Comp Cams made a fortune on their 'High Energy' series; those simply raised mean cylinder pressure on engines like yours is stock and really did wake things up. Several folk make similar now, but if you change heads and bump the squeeze, theres no need to use that type of stick. Look around, read carefully and think...dont get caught up in too much cam for that groove sound if youre gonna actually drive the car...not that I would know anything about that you understand...

Just my 2 pence, and remember, my advice is worth exactly what it costs you!

Having taken all the above into consideration I will not be going Ali Heads for the immediate future as a good set cost more than I am prepared to fork out especially given the other projects that I have on the go that also need a bucket load of money spending on them and I need reliability as well.
Looking on a c3 forum in the states one of the best options is a set of Vortec heads but I already have the inlet for the older version so I'll stick with headers, inlet, air cleaner, carb and timing tweeks, true dual exhaust and some tarty .

As for air cleaners go take a look at the engine masters episode on air cleaners on you tube, it was a bit of an eye opener to me, need to get me a stainless steel salad bowl